I think you got it
Click on the Smart Album for the Park you want to see and if you have Date set as the Sort then all in that Album will show in order by the metadata assigned by your camera. Even if you just Clicked on the whole Library where all of your 1,000's of photos show at once you could scroll by Date to the group for that date. The Date shows in the middle of the thumbnails as you scroll. One good thing about iPhoto is if you don't like the way you have it set up you can change it to do things a different way without messing up your photos. When I first started to use iPhoto I imported all my photos at one time, I like, you thought " now what, I got a real mess on my hands" and I only have a bout 2,000 photos at that time. But with a little thought I was able to get it all organized and into Smart Folders with Keywords in less that an hour. I have since made some changes and added more Smart Albums and Keywords and found out how easy it is to find any photo I want in just a few seconds. We travel a lot so I use States as smart Albums for the most part and the first keyword I assign to new photos is the State. If I import a photo of a family member the first Keyword is Family, then maybe Kids or Grandkids. You can add Keywords as you find a need for them or even delete them if you want.
Click on the Smart Album for the Park you want to see and if you have Date set as the Sort then all in that Album will show in order by the metadata assigned by your camera. Even if you just Clicked on the whole Library where all of your 1,000's of photos show at once you could scroll by Date to the group for that date. The Date shows in the middle of the thumbnails as you scroll. One good thing about iPhoto is if you don't like the way you have it set up you can change it to do things a different way without messing up your photos. When I first started to use iPhoto I imported all my photos at one time, I like, you thought " now what, I got a real mess on my hands" and I only have a bout 2,000 photos at that time. But with a little thought I was able to get it all organized and into Smart Folders with Keywords in less that an hour. I have since made some changes and added more Smart Albums and Keywords and found out how easy it is to find any photo I want in just a few seconds. We travel a lot so I use States as smart Albums for the most part and the first keyword I assign to new photos is the State. If I import a photo of a family member the first Keyword is Family, then maybe Kids or Grandkids. You can add Keywords as you find a need for them or even delete them if you want.